From the latest BOX AFD just fo posterity
All eyes are on the latter half of the weekend as unsettled, likely
wintry weather returns to southern New England. All is
predicated on the evolution of a low pressure system that takes
form in the lee of the Rockies on Saturday before crossing the
midwest on Sunday and New England Monday. Along the frontal
boundary a secondary triple point low is generated near the
Delmarva late Sunday which will cross near or adjacent to our
south coast Mon/Tue bringing both rain and snow. Early Sunday
the high moves overhead before being pushed out by the
approaching low. Clouds push in by daybreak ahead of the
precipitation but may be late enough to drop Sunday morning`s
low temps to radiate a few degrees cooler than otherwise. Precip
moves in from west to east by late morning/afternoon into
Sunday evening, with the best chance for heavier precip Sunday
night and Monday. Numerical guidance continues to indicate
potential for our first real impactful winter storm of the
season, though the details are uncertain; as we approach a
significant snowfall is looking like a better and better
probability for interior locations, while several factors would
lead us to believe those in the lower elevations/closer to the
coast will be dealing with some kind of unpleasant snow/rain
combo or mostly rain. The GFS continues to be further north with
the warm low level air, keeping the significant snow confined
mostly to the slopes of the Berkshires and Worcester Hills,
while the EC paints a cooler picture with snow further south but
mostly rain for the south coast/coastal plain. At this point
the forecast will continue to be based on a blend of these
solutions, which would, given the cold antecedent airmass, start
most everyone as snow initially before switching to a rain snow
mix or a all rain outside of northern/western MA. As the system
exits to the east cold air will be wrapped around the backside
on N/NW winds meaning a likely changeover back to snow for most
everyone late Monday into early Tuesday. Given the trend in
recent model runs to slow the progression of the trough and keep
the parent low further north for longer, and the relatively
warm ocean waters this early in the season, am leaning toward a
mainly interior snow event with this system. However, there`s
still plenty to be worked out with this system, including how
strong the winds will be, potentially gusting 25 to 35 mph. Stay
tuned.
